The present disclosure generally relates to surgery on body tissues and organs. More particularly, the present disclosure relates to devices and methods for engaging tissue of an organ, for example for positioning an organ in a desired orientation or for temporarily immobilizing a local area of tissue subject to motion, such as the heart wall, which permits a surgical procedure to be performed on that local area of tissue.
Approximately 300,000 patients in the United States undergo coronary artery bypass grafting operations every year. Conventional coronary artery bypass graft operations require the beating of the heart be ceased during the procedure. A heart-lung machine is used to pump and oxygenate the patient's blood while the heart is stopped. More recently, off-pump surgery, or beating heart surgery, has become an attractive alternative to traditional heart-lung machine procedures.
One challenge in beating heart coronary artery bypass graft surgery is that it can be difficult to suture or sew on a beating heart. The surgeon must use a “stabilization” system to keep the heart steady. The stabilization system typically consists of a heart positioner and a tissue stabilizer. The heart positioner guides and holds the heart in a position that provides best access to blocked arteries. The tissue stabilizer holds a small area of the heart stationary while a surgeon attaches a transplanted vessel around blockages in one or more coronary arteries, providing the surgeon with an unimpeded view of the stabilized suture site.
Some tissue stabilizers are designed to immobilize epicardial tissue in the immediate vicinity of an anastomosis site through a pressure-type stabilizer employing a simple mechanical fork. Such a device stabilizes the heart by pressing the fork downwards onto the heart surface. The fork is typically mounted to an elongated arm, which in turn is typically mounted to a retractor holding the patient's ribs apart to create an operative window. Angular movement of the arm relative to the retractor in some cases is accomplished by means of a turret, which may be clamped in a desired rotational position. Longitudinal movement of the arm relative to the retractor is typically allowed as well, and clamping mechanisms are typically provided to allow clamping of the arm to the turret and locking of the fork relative to the arm. Exemplary pressure tissue stabilization devices are disclosed in U.S. Pat. Nos. 6,036,641 and 6,876,332.
More recently, suction-based tissue stabilizers have gained wide-spread acceptance, such as the Medtronic Octopus® Tissue Stabilizer (available from Medtronic, Inc.), and employ a comparatively long, flexible, articulating arm carrying a pair of suction paddles or pods at its distal end. The suction pods are fluidly connected to a source of negative pressure. During use, the arm is typically secured to a retractor holding the patient's ribs apart to create an operative window. The pods are placed on opposite sides of the anastomosis site, and suction is applied to grip and immobilize the surface of the heart. Thereafter, tension is applied along the length of the arm to lock the arm in a desired spatial orientation and to lock the position of the pods relative to the arm. Examples of such devices are described in U.S. Pat. Nos. 6,464,629 and 6,866,628, the entire teachings of both of which are incorporated herein by reference. Other examples of suction-type tissue stabilizers are described in U.S. Pub. No. 2008/0139879 entitled “Methods and Devices for Stabilizing Tissue”, incorporated herein by reference in its entirety. With these devices, the suction-applying pods are carried by a generally Y-shaped head provided as part of head-link assembly that is rotatably coupled to a collet carried by the articulating arm. With these constructions, a tension element is operable by the surgeon to selectively clamp a spherical base of the head-link assembly relative to the collet. Upon loosening of the tension element, the head-link assembly can be rotated and/or pivoted at virtually any angle (i.e., yaw, pitch, and roll) above a plane perpendicular the collet, promoting multiple device positions including what is commonly referred to as pods-up, pods-down, and pods-to-the-side applications. Examples of such suction tissue stabilizers are available from Medtronic, Inc. under the trade name Octopus® Evolution™ Tissue Stabilizer.
Although available tissue stabilizers for use with off-pump coronary artery bypass graft surgical procedures are highly viable, any improvements will be well-accepted. For example, surgeons desire the ability to slightly stretch tissue of the heart between the suction pods of the tissue stabilizer, and may prefer to accomplish spreading of the pods without directly handling the head-link assembly.